Molded bobbin



. May 28, 1957 P. c. coNsoLETTl 2,793,822

MOLDED BOBBIN Filed June 25, 1953 United states Pata-1ro MOLDED BoBBlN Paul C. Consoletti, Milford, Mass., assignor to Draper Corporation, Hopedale, Mass., a corporation of Maine Application June 23, 1953, Serial No. 363,582

3 Claims. (Cl. 242-118.32)

technique and for obtaining better thread holding char-r acteristics for the bobbin itself. Y

It is an object of the invention to devise a bobbin which shall possess improved thread retaining characteristics and also one in which the surface is better adapted to; permit drawing of thread therefrom with greater uniformity of tension.

A further object is that of so devising a bobbin thatI it may be easily cast `from plastic` molding compounds and so that the flash left after' removal from the mold may be very easily and cleanly ground off or otherwise removed.

Other objects will become apparent from the following disclosure.

VPlastic bobbinsY are now used to Vsome extent in the textile industry and filling or shuttle bobbins are so made although thercost thereof is fairly high and in instances, theflash leftl on the finished bobbin has been a source of trouble especially when the thread wound thereon has been of fine count or of easily destructible nature. Thread wound as a filling package is drawn off over the bobbin end and such bobbins must be provided with taper toward the end. To prevent unintended and too rapid thread removal, the tapered portion of the bobbin barrel is circumferentially grooved or indented. These grooves are necessarily spaced so that there is a different effect upon the thread being drawn from the bobbin according to whether or not it is being drawn from the grooved or the raised or land portions thereof.

According to the invention, the grooved part of the bobbin barrel is modified by interrupting the grooves along at least one and preferably two areas lengthwise of the bobbin.

The grooves are preferably formed so they are of increasing depth as they recede from the non-grooved portions or surfaces and extend about the greater portion of the bobbin barrel circumference leaving only about to more or less, of the surface thereof, preferably at diametrically opposed sides of the bobbin, smooth or ungrooved.

For molding, the construction of the mold is so arranged as to take advantage of these non-grooved areas. The mold is formed so as to be parted on a longitudinal center plane centered at the said plain-surfaced or nongrooved areas. Thus the flash formed at the mold parting line is confined to a portion of the bobbin barrel where there are no grooves and may be ground olf or otherwise removed with a minimum of effort, time and expense, also, with greater certainty that no vestige of the liash line shall remain to cause damage to the thread. When attempting to remove a flash line running along the undulating, grooved surfaces, a clean job is diicult and requires time, care and, of course, expense. Hand work of that sort can run costs to a prohibitive ligure.

By breaking the continuity of the grooves, withdrawal of the thread is facilitated since at each turn drawn from the bobbin, the thread, if at a grooved portion thereof, is affected by the alternating interference of the grooved and non-grooved surfaces. This breaks the tendency the thread has to stick at or to Withdraw differently at the grooves as compared to the lands.

The invention will now be described in detail by reference -to the accompanying figures of drawing wherein:

Fig. 1 is an elevation of a bobbin embodying the invention.

Fig. 2 is a similar View showing another form the inventionA may take.

Fig. 3 is a section taken at line 3--3, either as applied to. Fig. l or Fig. 2.

Fig. 4 is a section at the same point, but showing the bobbin before removal of flash.

Fig. 5 is an enlarged view showing surface details of the bobbin of Fig. l.

Fig. 6 is a similar View applying to Fig. 2.

Fig. 7 is a section showing a part of a mold in which the bobbin according to the invention is cast.

Now referring to Fig. 1, a bobbin 10 is comprised of a butt 11 and barrel 12, the butt being provided with rings 13 for a purpose well known to those skilled in the textile arts. The bobbin is cored centrally to admit of being driven on a spindle and a filling wound package may be formed on the barrel being started just above the butt and continuing to a point near the bobbin tip in known manner. The barrel is preferably cylindrical for part of its length adjacent the butt and then is tapered slightly to the tip. A series of grooves or indentations 14 are formed along the length of the bobbin. These extend circumferentially and may or may not be confined to the tapered portion. They are primarily for the purpose of restraining the coils of the package, especially at the tapered part thereof, from slipping off prematurely.

In a Wooden bobbin which must for practical reasons be turned in a lathe, these grooves are continuous, although with special turning equipment they may be formed as herein described. In molding the matrix is so formedas to cause the formation of grooves 14, Fig. 5, varying in depth from a maximum at the points adjacent 15 and then tapering and becoming more shallow to a point 16 where they actually discontinue. These grooves spaced oppositely about the barrel are thus spaced to leave a longitudinally extending strip 17 which is actual ly a part of the cylindrical or conical contour of the bobbin barrel being ungrooved. The grooves may be staggered at opposite semi-circumferences if desired.

Now referring to Fig. 7, Without resorting to unnecessary detail, the general scheme of molding involves opposed mold parts 18 and 19 which separate at line 20, it being possible to inject the molding compound in any known way. The mold or matrix has ridges or lands 21 and 22 which form the grooves. The spaces intermediate are all a part of a cylindrical confining surface between which and the core or mandrel 23 the compound is injected.

Since it is never practicable to form a mold in a manner to prevent a slight tendency toward leakage at the parting line, a projecting tin known as flash will appear at that plane, one at each side. In Fig. 4 such flash is shown projecting at 24 and 25. Of course, such projections must be removed before the bobbin may be used and since the improved grooving at the same time leaves an appreciable non-grooved surface at the critical area, it is a simple matter to grind the excess material away leaving a perfect surface for the thread. Such operation is speedy, effective and inexpensive when compared to a method of grinding along the lands and into the grooves, or tumbling for excessive periods of time, in

which event, much of the entire bobbin had to be removed to eliminate most of lthe flash.

Now referring to Figs. 2 and 6, a modied form of grooved surface is shown. The -lands 26 arearchedso that the grooves 27 are formed thereby and really constitute very shallow Vs. However, the same general scheme is followed in that the grooves are started `and discontinued twice within each circumference leaving an area 28 similar to that at 17, Figs. 1 and l5. The molding leaves the flash at this area 18, also at one 180 removed.

In winding the package, the thread is deposited on the entire exterior surface of the barrel so that some convolutions are confined in the grooves although the .most lay upon the lands. The fact the thread is brought to the outer cylindrical surface at the laying of each convolution during winding and also during unwinding, makes for less difference in tension conditions of a convolution at the grooves as compared to one at the'lands. Thus the performance of a loom in the shuttle of which a bobbin of this type is used is noticeably improved. Filling breakage is reduced and the filling tension is more uniform during weaving.

The molding compounds may comprise any of the thermoplastic or thermosetting plastics suitable for the purpose. The invention also applies to die cast bobbins and to bobbins other than filling or shuttle bobbins, for example, to warp bobbins and others. The grooves and lands may be otherwise formed, the well known stepped bobbin barrels being advantageously molded in this way and by the same process.

While one embodiment of the invention has been disclosed, it is to be understood that the inventive concept may be carried out in a number of ways. This invention is, therefore, not to be limited to the precise details described, but is intended to embrace all variations and modifications thereof falling within the spirit of the invention and the scope of the claims.

I claim:

1. A bobbin molded from a plastic material and hav- I l ing a barrel upon which a thread package may be wound, said barrel having along at least a part of its length spaced, thread receiving grooves, said grooves extending about less than one half the barrel circumference at each side of a non-grooved, cylindrical surface extending lengthwise of the bobbin, said non-grooved surface being radially spaced from the center of said barrel substantially the same distance as those surface areas between thread receiving grooves.

2, A bobbin molded from a plastic material and having a butt portion and a barrel upon which a thread package may be wound, said barrel having along at least a part of its length spaced, thread receiving grooves, said grooves extending about less than one half the barrel circumference at each side of a non-grooved, cylindrical surface extending lengthwise of the bobbin, said nongrooved surface being radially spaced from the center of said barrel substantially the same distance as those surface areas between thread receiving grooves.

3. A bobbin molded from a plastic material .and having a butt portion and a tapered barrel upon which a thread package may be wound, said tapered barrel having along its length spaced thread receiving grooves, said grooves yextending for a part only of the circumference of the barrel to leave an ungroovedlportion at opposite sides thereof, said `non-grooved por-tion being radially spaced from the center of said barrel substantially the same distance as those surface areas between thread receiving grooves.

References Cited in the file of this patent UNITED STATES PATENTSy 1,135,962 Aylsworth Apr. `13, 191'5 1,916,692 Scribner July 4, 1933 2,195,240 Chaplin et al. Mar. 26, 194() 2,605,979 Gartrell Aug. 5, 1952 FOREIGN PATENTS 192,829 Switzerland Nov. 16, 1937 67,754 Denmark Oct. 4, 1948 

